Natural diamond is produced in high pressure and high temperature volcanic shafts, and the scarcity and cost of natural diamond has stimulated synthetic diamond research for over 100 years. Diamond synthesis requires high energy inputs, as diamond is not the thermodynamically stable form of carbon at ambient conditions. Diamond is, however, more thermodynamically stable than amorphous carbon Generally, diamond is synthesized at high pressure (˜1-10 GPa) where diamond is the thermodynamically preferred form of carbon, and at high temperatures (T>2000 K) to overcome the kinetic barriers of the solid-phase conversion of graphite to diamond. In addition to the high-pressure, high-temperature conversion from graphite into diamond, synthetic diamond is currently produced via either chemical vapor deposition or explosive detonation.
Diamonds are valued for superior hardness and thus have uses in many industries. For example, diamonds are used as abrasives as well as in cutting tools and drills. Diamond size is important in defining the specific uses of the material and smaller sizes are particularly desired as fine abrasives, for instance. However, methods of producing diamond materials and other forms of diamond, including crystalline carbon, nanocrystalline diamond and “diamond-like carbon,” often involve very high pressure and temperatures, making their synthesis difficult.
Thus, there is a continuing need for methods and compositions relating to synthesis of carbon-based structures including crystalline carbons, nanocrystalline diamond and diamond-like carbons. In particular, there is a continuing need for relatively low system pressure methods for synthesis of carbon-based structures including crystalline carbons, nanocrystalline diamond and diamond-like carbons.